sslobodr | d046be8 | 2019-01-16 10:02:22 -0500 | [diff] [blame] | 1 | // Copyright 2015 The etcd Authors |
| 2 | // |
| 3 | // Licensed under the Apache License, Version 2.0 (the "License"); |
| 4 | // you may not use this file except in compliance with the License. |
| 5 | // You may obtain a copy of the License at |
| 6 | // |
| 7 | // http://www.apache.org/licenses/LICENSE-2.0 |
| 8 | // |
| 9 | // Unless required by applicable law or agreed to in writing, software |
| 10 | // distributed under the License is distributed on an "AS IS" BASIS, |
| 11 | // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 12 | // See the License for the specific language governing permissions and |
| 13 | // limitations under the License. |
| 14 | |
| 15 | // Package flags implements command-line flag parsing. |
| 16 | package flags |
| 17 | |
| 18 | import ( |
| 19 | "flag" |
| 20 | "fmt" |
| 21 | "net/url" |
| 22 | "os" |
| 23 | "strings" |
| 24 | |
| 25 | "github.com/coreos/pkg/capnslog" |
| 26 | "github.com/spf13/pflag" |
| 27 | ) |
| 28 | |
| 29 | var ( |
| 30 | plog = capnslog.NewPackageLogger("github.com/coreos/etcd", "pkg/flags") |
| 31 | ) |
| 32 | |
| 33 | // DeprecatedFlag encapsulates a flag that may have been previously valid but |
| 34 | // is now deprecated. If a DeprecatedFlag is set, an error occurs. |
| 35 | type DeprecatedFlag struct { |
| 36 | Name string |
| 37 | } |
| 38 | |
| 39 | func (f *DeprecatedFlag) Set(_ string) error { |
| 40 | return fmt.Errorf(`flag "-%s" is no longer supported.`, f.Name) |
| 41 | } |
| 42 | |
| 43 | func (f *DeprecatedFlag) String() string { |
| 44 | return "" |
| 45 | } |
| 46 | |
| 47 | // IgnoredFlag encapsulates a flag that may have been previously valid but is |
| 48 | // now ignored. If an IgnoredFlag is set, a warning is printed and |
| 49 | // operation continues. |
| 50 | type IgnoredFlag struct { |
| 51 | Name string |
| 52 | } |
| 53 | |
| 54 | // IsBoolFlag is defined to allow the flag to be defined without an argument |
| 55 | func (f *IgnoredFlag) IsBoolFlag() bool { |
| 56 | return true |
| 57 | } |
| 58 | |
| 59 | func (f *IgnoredFlag) Set(s string) error { |
| 60 | plog.Warningf(`flag "-%s" is no longer supported - ignoring.`, f.Name) |
| 61 | return nil |
| 62 | } |
| 63 | |
| 64 | func (f *IgnoredFlag) String() string { |
| 65 | return "" |
| 66 | } |
| 67 | |
| 68 | // SetFlagsFromEnv parses all registered flags in the given flagset, |
| 69 | // and if they are not already set it attempts to set their values from |
| 70 | // environment variables. Environment variables take the name of the flag but |
| 71 | // are UPPERCASE, have the given prefix and any dashes are replaced by |
| 72 | // underscores - for example: some-flag => ETCD_SOME_FLAG |
| 73 | func SetFlagsFromEnv(prefix string, fs *flag.FlagSet) error { |
| 74 | var err error |
| 75 | alreadySet := make(map[string]bool) |
| 76 | fs.Visit(func(f *flag.Flag) { |
| 77 | alreadySet[FlagToEnv(prefix, f.Name)] = true |
| 78 | }) |
| 79 | usedEnvKey := make(map[string]bool) |
| 80 | fs.VisitAll(func(f *flag.Flag) { |
| 81 | if serr := setFlagFromEnv(fs, prefix, f.Name, usedEnvKey, alreadySet, true); serr != nil { |
| 82 | err = serr |
| 83 | } |
| 84 | }) |
| 85 | verifyEnv(prefix, usedEnvKey, alreadySet) |
| 86 | return err |
| 87 | } |
| 88 | |
| 89 | // SetPflagsFromEnv is similar to SetFlagsFromEnv. However, the accepted flagset type is pflag.FlagSet |
| 90 | // and it does not do any logging. |
| 91 | func SetPflagsFromEnv(prefix string, fs *pflag.FlagSet) error { |
| 92 | var err error |
| 93 | alreadySet := make(map[string]bool) |
| 94 | usedEnvKey := make(map[string]bool) |
| 95 | fs.VisitAll(func(f *pflag.Flag) { |
| 96 | if f.Changed { |
| 97 | alreadySet[FlagToEnv(prefix, f.Name)] = true |
| 98 | } |
| 99 | if serr := setFlagFromEnv(fs, prefix, f.Name, usedEnvKey, alreadySet, false); serr != nil { |
| 100 | err = serr |
| 101 | } |
| 102 | }) |
| 103 | verifyEnv(prefix, usedEnvKey, alreadySet) |
| 104 | return err |
| 105 | } |
| 106 | |
| 107 | // FlagToEnv converts flag string to upper-case environment variable key string. |
| 108 | func FlagToEnv(prefix, name string) string { |
| 109 | return prefix + "_" + strings.ToUpper(strings.Replace(name, "-", "_", -1)) |
| 110 | } |
| 111 | |
| 112 | func verifyEnv(prefix string, usedEnvKey, alreadySet map[string]bool) { |
| 113 | for _, env := range os.Environ() { |
| 114 | kv := strings.SplitN(env, "=", 2) |
| 115 | if len(kv) != 2 { |
| 116 | plog.Warningf("found invalid env %s", env) |
| 117 | } |
| 118 | if usedEnvKey[kv[0]] { |
| 119 | continue |
| 120 | } |
| 121 | if alreadySet[kv[0]] { |
| 122 | // TODO: exit with error in v3.4 |
| 123 | plog.Warningf("recognized environment variable %s, but unused: shadowed by corresponding flag", kv[0]) |
| 124 | continue |
| 125 | } |
| 126 | if strings.HasPrefix(env, prefix+"_") { |
| 127 | plog.Warningf("unrecognized environment variable %s", env) |
| 128 | } |
| 129 | } |
| 130 | } |
| 131 | |
| 132 | type flagSetter interface { |
| 133 | Set(fk string, fv string) error |
| 134 | } |
| 135 | |
| 136 | func setFlagFromEnv(fs flagSetter, prefix, fname string, usedEnvKey, alreadySet map[string]bool, log bool) error { |
| 137 | key := FlagToEnv(prefix, fname) |
| 138 | if !alreadySet[key] { |
| 139 | val := os.Getenv(key) |
| 140 | if val != "" { |
| 141 | usedEnvKey[key] = true |
| 142 | if serr := fs.Set(fname, val); serr != nil { |
| 143 | return fmt.Errorf("invalid value %q for %s: %v", val, key, serr) |
| 144 | } |
| 145 | if log { |
| 146 | plog.Infof("recognized and used environment variable %s=%s", key, val) |
| 147 | } |
| 148 | } |
| 149 | } |
| 150 | return nil |
| 151 | } |
| 152 | |
| 153 | // URLsFromFlag returns a slices from url got from the flag. |
| 154 | func URLsFromFlag(fs *flag.FlagSet, urlsFlagName string) []url.URL { |
| 155 | return []url.URL(*fs.Lookup(urlsFlagName).Value.(*URLsValue)) |
| 156 | } |
| 157 | |
| 158 | func IsSet(fs *flag.FlagSet, name string) bool { |
| 159 | set := false |
| 160 | fs.Visit(func(f *flag.Flag) { |
| 161 | if f.Name == name { |
| 162 | set = true |
| 163 | } |
| 164 | }) |
| 165 | return set |
| 166 | } |